If you’ve never noticed it, you will now. It’s everywhere.
The word ‘Mens,’ absent an apostrophe, indicating a restroom for the male persuasion.
It looks ridiculous. Right?
‘Men’ is already plural. Stick an S on the end without an apostrophe is like putting a hat on a hat.
The equivalent ‘Ladies’ is fine, since ‘Lady’ isn’t already plural. ‘Womens’ would be just as wrong as ‘Mens,’ but I can’t ever remember seeing ‘Womens.’
But ‘Mens’ is honestly everywhere.